It is fatiguing for a person confined to a wheelchair to sit continuously in the same position. Both rest and relief can be obtained by the change of posture that occurs when the chair is tilted backward. For this reason, wheelchairs have been designed which permit the occupant to change the disposition of the seat by tilting same backward or forward and also be raising or lowering the leg rests. Examples of the prior art in this respect are disclosed in the following U.S. Pat. Nos. 3,147,039 to P. Smith et al of Sept. 1, 1964; 3,198,575 to H. Hawkins of Aug. 3, 1965; 3,269,768 to J. Kinney of Aug. 30, 1966; 3,284,126 to S. Piazza of Nov. 8, 1966; 3,640,566 to G. Hodge of Feb. 8, 1972; and 3,858,938 to O. Kristensson et al of Nov. 28, 1972.
Wheelchairs of the type involved must be rugged, relatively light in weight, easily manipulated by the occupant or an attendant and the reclining seat or chair therein should be as convenient to adjust as non-mobile chairs of the same type. To achieve these objects, prior art wheelchairs of the type involved have, in general, utilized frames which support both the wheels and the seat components wherein the frame usually extends on each side above the seat which depends therefrom or is otherwise supported by the frame. Such wheelchairs must either have the two opposite sides of the frame connected by a truss-like structure or utilize other means for rigidizing same; otherwise they tend to develop a side-to-side wobble especially after continued use. Although this is correctible by known mechanisms such as trusses or the like for stiffening and rigidizing the structure, the resulting composite wheelchair is frequently heavier than desirable in comparison with wheelchairs not having reclining seats whereby rigidity of the frame is more easily facilitated.
The instant invention is directed to a wheelchair structure wherein the seat is of a reclining type and which, at the same time, does not differ significantly in overall weight from nonreclining types of wheelchairs and which is, moreover, a highly rigid and wobble-resistant structure.